Project Summary and Relevance: HIV-1, the cause of AIDS, remains a formidable foe since its identification in the early 1980's. The virus' ability to rapidly mutate allows for resistance to conventional therapy, and it has also made it difficult to generate effective vaccines against HIV-1. Moreover, even when combination anti-retroviral therapy is effective in preventing viral replication, HIV-1 cannot be eliminated from the host because it sits in wait in latently infected CD4 T cells. Like many parasites, HIV-1 relies upon host transcription factors in order to replicate. The HIV-1 long terminal repeat (LTR)/transcriptional promoter, particularly the region most proximal to the transcriptional start site, is critically important for viral transcription. Because of this, the proximal LTR is one of the least mutated regions of the HIV-1 genome in virulent strains. Recently, we and others have demonstrated the ability of nuclear factor of activated T cells (NFAT) transcription factors to bind to the proximal HIV-1 LTR and to act as positive regulators of HIV-1 transcription. This effect on HIV-1 transcription is markedly reduced in vitro by cyclosporine A and the VIVIT peptide, 2 relatively NFAT-specific inhibitors. However, little is known about the relative roles of the various NFAT family members on HIV-1 in vivo, particularly in primary CD4 T cells. Based on our in vitro binding data, we hypothesize that NFAT2 preferentially binds the HIV-1 LTR in vivo and augments HIV-1 transcription. We propose to analyze the ability of NFAT proteins to bind to the HIV-1 LTR in vivo by chromatin immunoprecipitation (Aim 1). In addition, we have identified a novel binding site for the Th2- specific transcription factor, c-maf, located adjacent to the proximal NFAT sites. We plan to investigate the role of c-maf transcription factor for its capacity to bind the HIV-1 LTR and augment HIV-1 transcription by partnering with NFAT2 (Aim 2). The proposed studies will yield novel therapeutic approaches to HIV-1 inhibition, and to redirecting the detrimental Th2 switch, which takes place over the course of HIV-1 infection. This will allow for better control of viral burden and the consequent morbidity and mortality. Relevence: These studies will be useful for inhibiting viral transcription/expression in HIV-1 infected individuals. Moreover, they will help restore immune function directed against intracellular pathogens. Lastly, they will provide knowledge regarding the use of NFAT inhibitors (cyclosporin) for prevention of graft rejection in HIV. [unreadable] [unreadable] [unreadable]